prune targets in the transition model that would cause the same song to be repeated twice

server/djrandom/model/markov.py

@@ -54,9 +54,13 @@ class MarkovModel(object):
             norm_vec = []
             tot = sum(target_map.itervalues())
             cur = 0
-            for k, v in target_map.iteritems():
-                cur += float(v) / tot
-                norm_vec.append((cur, k))
+            for target, count in target_map.iteritems():
+                # We explicitly drop this target to avoid repeating
+                # the same song more than once.
+                if target == key[-1]:
+                    continue
+                cur += float(count) / tot
+                norm_vec.append((cur, target))
             norm_map[key] = norm_vec
         self._map = norm_map